Aqueous solutions which flow at a controlled rate under a given shear stress are required throughout a variety of industrial applications. Such control of viscosity of water is achieved by adding to water agents such as clays, large amounts of polar organic compounds such as polyacrylates or high concentrations of salts. With the appropriate additives, these aqueous solutions can suspend large amounts of a solid phase and form a thermodynamically stable mixture. These aqueous solutions suspend finely divided solids and will flow slowly when exposed to shear stress. Such solutions, free of solids, also flow more uniformly in situations where numerous paths providing different resistances to flow are open to the fluids. There are, however, numerous applications for polymers in the dry state. Most water soluble polymers are not useful as plastic solids or in the dry state. This invention is directed to materials that are so useful.
Each of the conventional agents mentioned above as useful in controlling fluid flow has attendant disadvantages, particularly when used to recover oil from subterranean wells. Hence, a need continues to exist for new agents which are capable of suitably thickening water and aqueous solutions having the desirable properties outlined below but which are free of attendant disadvantages. Further, many materials are used to make objects of manufacture with functional strength and resistance properties. These materials are usually not, however, polymers which can be dissolved in water. Further, most of these objects are made from expensive synthetic chemicals rather than cheaper natural compounds like lignin. Objects of manufacture which contain large amounts of lignin are desirable, inexpensive products because of low raw materials cost.